Throughout history, investors have gobbled up gold for one primary reason: To bet on catastrophe.

Since it became legal for Americans to own in 1975, gold has served as a buffer against inflation and a protection from bank failure.

Even in earlier times, gold was always a safe haven, a fallback for those with little faith in paper money.

So what then can be made of gold's recent run-up in value, which saw in May the shiny metal reach its highest level since the 1980s?

"There's simply no reason to buy it except to bet on disaster," said Peter Bernstein, author of "The Power of Gold" and a gold historian. "It's an expensive thing to do. It pays no income and there's storage costs. … The people who buy gold are simply the people who have no faith in paper currencies."

But while the tech bust, 2001 recession and recent inflation have given some investors jitters, Bernstein wonders whether the traditional reasons for buying gold hold true this time around.

"There's something very strange about what's happening to gold right now," he said. "In this episode it's gone up lock step with other commodities. That's different form the '70s and '80s."

For millennia, human beings have seen gold as a symbol of wealth. That led to a long period of time when gold was linked to money. In theory, for example, a dollar could be exchanged for a certain amount of gold. When the link was largely broken in the 1970s, investing in gold took off.

Gold's economic importance, however, dates back more than 6,000 years.

"Gold was money before there were central banks," said Michael Kosares, president of USAGold-Centenniel Precious Metals, a gold trading company in Denver. "In the modern era, people see it as a final payment. It has a value that doesn't come out of thin air and can't be undermined, and that's not ever going to change."

As early as 4000 B.C., societies in what's now Eastern Europe were mining gold in the Transylvanian Alps and using it to create decorative objects.

Gold was first used as money about 15 centuries before the birth of Christ, when a coin called the shekel became a standard unit of measure in the Middle East.

In the United States, the dollar's tie to gold dates back to the Coinage Act of 1792, under which Americans could exchange their dollars for gold. But to prevent U.S. citizens from doing so and possibly causing a bank run, it became illegal starting in 1933 for them to own gold.

A key series of decisions that would pave the way for gold investing began in 1971. That year, President Richard M. Nixon devalued the dollar versus gold, a move he would make again two years later. Then, in 1975, it became legal again for Americans to own gold.

As a result, trading of gold futures began in New York and Chicago. For two years, a recession held gold's price in check, but uncertainty about inflation caused it to take off in the late 1970s.

"When American citizens gained the right to own gold back, they pursued it aggressively," said Dan Vought, a futures analyst at A.G. Edwards Inc. in St. Louis. "With inflation as a concern, they saw it as a safe instrument."

By 1979, the world was in a full-blown monetary crisis, writes Kosares, the author of "The ABCs of Gold Investing." Interest in gold soared, and the price peaked at $875 an ounce that year, compared to just over $100 four years earlier.

In the 1980s and '90s, interest in gold generally cooled. An exception was 1987, when a stock market crash and bank failures caused the price to spike.

The long-running bull market of the 1990s also made gold investing seem antiquated.

But in the wake of the tech bust earlier this decade, a resurgence began. The price of gold has risen consistently over the last several years and peaked in May.

Kosares thinks many investors fear burgeoning inflation and are again finding gold to be a secure place for money. He also believes a cyclical shift has occurred where gold and other commodities are falling back into favor.

"Very few people buy gold because they want to make a bunch of money on it. They buy it to protect themselves," he said. "In terms of gold, I think we're entering a bull market trend."